Hello jtsvec, good to meet you.
Not sure personally of any northern ky trails but I'm sure someone on here will help out. I lived in Ft Thomas for a while and there were some trails down to the river near/behindTower Park. Might try that area?
As for central ky, come on down to the gorge Red River Gorge) sometime. I am new to getting out on the trails too but it seems there are some good groups if people on here who hit the gorge and Redbird area ever now and again.
Let me know if you plan to head down this way sometime...